The X-47B remains the US military's principle vanguard for a potential new age of stealthy, autonomous combat aircraft. The UCAS-D programme aims to prove the viability of operating such vehicles from aircraft carrier decks.

"Unveiling the first X-47B UCAS aircraft signals a sea change in military aviation, made possible through the navy's vision and leadership," said Scott Winship, Northrop VP and navy UCAS programme manager.

The UCAS-D appears to have survived a budget crisis in June, and the USN has recently expanded the programme to include an autonomous aerial refueling demonstration.